Methods The 3-(4,5-dimethylthiazol- 2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used to determine the in vitro antitumor effects of acetylshikonin on human lung adenocarcinoma cell line A549, human hepatocellular carcinoma cell line Bel-7402, human breast adenocarcinoma cell line MCF-7 and mouse Lewis lung carcinoma (LLC) cell line. C57BL/6 mice with LLC model were used to study the in vivo antitumor effects of acetylshikonin. The expression of bax, bcl-2 and caspase-3 proteins in LLC tissue was determined with immunohistochemical staining.

DiscussionRecent studies showed that shikonin derivatives acted on multiple tumor cells and triggered multiple cell death pathways. Therefore, shikonin derivatives are potentialcancer treatment agents. Acetylshikonin is a main shikonin derivative of Arnebia euchroma (Royle) Johnst. Other research on shikonin derivatives also demonstratedthat acetylshikonin inhibited K562 and HL-60 tumor growth [8]; however, acetylshikonin had not been studied in detail. The present study indicated that acetylshikoninhad in vitro and in vivo antitumor effects. Acetylshikonin possessed a high level of cytotoxic activity in vitro.